Re: [dpdk-dev] [PATCH v2] net/vhost: fix vhost invalid state

["Chen, Junjie J" <junjie.j.chen@intel.com>]

> 
> 
> On 4/11/2018 6:53 PM, Junjie Chen wrote:
> > dev_start sets *dev_attached* after setup queues, this sets device to
> > invalid state since no frontend is attached. Also destroy_device set
> > *started* to zero which makes *allow_queuing* always zero until
> > dev_start get called again. Actually, we should not determine queues
> > existence by
> > *dev_attached* but by queues pointers or other separated variable(s).
> 
> I see two issues from your description:
> 
> - We shall fix the wrong use of dev_attached by commit 30a701a53737.
> - The allow_queuing is not set correctly. But I doubt if it's a real issue, as we do
> update the queue status in dev_start(), dev_stop(), and new_device(). Can you
> explain more?
The started is set to 0 in destroy_device in 30a701a53737 commit, so allow_queuing is always
set to 0 once update_queuing_status get called. We have to use "port start" to reset to 1.
> 
> >
> > Fixes: 30a701a53737 ("net/vhost: fix crash when creating vdev
> > dynamically")
> >
> > Signed-off-by: Junjie Chen <junjie.j.chen@intel.com>
> > ---
> > Changes in v2:
> > - use started to determine vhost queues readiness
> > - revert setting started to zero in destroy_device
> >   drivers/net/vhost/rte_eth_vhost.c | 61
> ++++++++++++++++++++-------------------
> >   1 file changed, 31 insertions(+), 30 deletions(-)
> >
> > diff --git a/drivers/net/vhost/rte_eth_vhost.c
> b/drivers/net/vhost/rte_eth_vhost.c
> > index 11b6076..ff462b3 100644
> > --- a/drivers/net/vhost/rte_eth_vhost.c
> > +++ b/drivers/net/vhost/rte_eth_vhost.c
> > @@ -528,10 +528,13 @@ update_queuing_status(struct rte_eth_dev *dev)
> >   	unsigned int i;
> >   	int allow_queuing = 1;
> >
> > -	if (rte_atomic32_read(&internal->dev_attached) == 0)
> > +	if (!dev->data->rx_queues || !dev->data->tx_queues) {
> > +		RTE_LOG(ERR, PMD, "RX/TX queues not exist yet\n");
> 
> Even it's not introduced in this patch, but I think we shall not report
> error log here.
if you attach one port with "port attach" (no vhost queue setup yet), and then execute 
"port stop", the queue status is not exist yet, right?
> 
> >   		return;
> > +	}
> >
> > -	if (rte_atomic32_read(&internal->started) == 0)
> > +	if (rte_atomic32_read(&internal->started) == 0 ||
> > +	    rte_atomic32_read(&internal->dev_attached) == 0)
> >   		allow_queuing = 0;
> >
> >   	/* Wait until rx/tx_pkt_burst stops accessing vhost device */
> > @@ -607,13 +610,10 @@ new_device(int vid)
> >   #endif
> >
> >   	internal->vid = vid;
> > -	if (eth_dev->data->rx_queues && eth_dev->data->tx_queues) {
> > +	if (rte_atomic32_read(&internal->started) == 1)
> >   		queue_setup(eth_dev, internal);
> > -		rte_atomic32_set(&internal->dev_attached, 1);
> > -	} else {
> > -		RTE_LOG(INFO, PMD, "RX/TX queues have not setup yet\n");
> > -		rte_atomic32_set(&internal->dev_attached, 0);
> > -	}
> > +	else
> > +		RTE_LOG(INFO, PMD, "RX/TX queues not exist yet\n");
> >
> >   	for (i = 0; i < rte_vhost_get_vring_num(vid); i++)
> >   		rte_vhost_enable_guest_notification(vid, i, 0);
> > @@ -622,6 +622,7 @@ new_device(int vid)
> >
> >   	eth_dev->data->dev_link.link_status = ETH_LINK_UP;
> >
> > +	rte_atomic32_set(&internal->dev_attached, 1);
> >   	update_queuing_status(eth_dev);
> >
> >   	RTE_LOG(INFO, PMD, "Vhost device %d created\n", vid);
> > @@ -651,23 +652,24 @@ destroy_device(int vid)
> >   	eth_dev = list->eth_dev;
> >   	internal = eth_dev->data->dev_private;
> >
> > -	rte_atomic32_set(&internal->started, 0);
> > -	update_queuing_status(eth_dev);
> >   	rte_atomic32_set(&internal->dev_attached, 0);
> > +	update_queuing_status(eth_dev);
> >
> >   	eth_dev->data->dev_link.link_status = ETH_LINK_DOWN;
> >
> > -	for (i = 0; i < eth_dev->data->nb_rx_queues; i++) {
> > -		vq = eth_dev->data->rx_queues[i];
> > -		if (vq == NULL)
> > -			continue;
> > -		vq->vid = -1;
> > -	}
> > -	for (i = 0; i < eth_dev->data->nb_tx_queues; i++) {
> > -		vq = eth_dev->data->tx_queues[i];
> > -		if (vq == NULL)
> > -			continue;
> > -		vq->vid = -1;
> > +	if (eth_dev->data->rx_queues && eth_dev->data->tx_queues) {
> > +		for (i = 0; i < eth_dev->data->nb_rx_queues; i++) {
> > +			vq = eth_dev->data->rx_queues[i];
> > +			if (!vq)
> > +				continue;
> > +			vq->vid = -1;
> > +		}
> > +		for (i = 0; i < eth_dev->data->nb_tx_queues; i++) {
> > +			vq = eth_dev->data->tx_queues[i];
> > +			if (!vq)
> > +				continue;
> > +			vq->vid = -1;
> > +		}
> >   	}
> >
> >   	state = vring_states[eth_dev->data->port_id];
> > @@ -792,11 +794,7 @@ eth_dev_start(struct rte_eth_dev *eth_dev)
> >   {
> >   	struct pmd_internal *internal = eth_dev->data->dev_private;
> >
> > -	if (unlikely(rte_atomic32_read(&internal->dev_attached) == 0)) {
> > -		queue_setup(eth_dev, internal);
> > -		rte_atomic32_set(&internal->dev_attached, 1);
> > -	}
> > -
> > +	queue_setup(eth_dev, internal);
> >   	rte_atomic32_set(&internal->started, 1);
> >   	update_queuing_status(eth_dev);
> >
> > @@ -836,10 +834,13 @@ eth_dev_close(struct rte_eth_dev *dev)
> >   	pthread_mutex_unlock(&internal_list_lock);
> >   	rte_free(list);
> >
> > -	for (i = 0; i < dev->data->nb_rx_queues; i++)
> > -		rte_free(dev->data->rx_queues[i]);
> > -	for (i = 0; i < dev->data->nb_tx_queues; i++)
> > -		rte_free(dev->data->tx_queues[i]);
> > +	if (dev->data->rx_queues)
> > +		for (i = 0; i < dev->data->nb_rx_queues; i++)
> > +			rte_free(dev->data->rx_queues[i]);
> > +
> > +	if (dev->data->tx_queues)
> > +		for (i = 0; i < dev->data->nb_tx_queues; i++)
> > +			rte_free(dev->data->tx_queues[i]);
> >
> >   	rte_free(dev->data->mac_addrs);
> >   	free(internal->dev_name);